1. Field of the Invention
The present invention relates to an apparatus and method for auto frequency calibration for a transducer, more particularly to, the apparatus and method enabling a micro controller to dynamically calibrate the frequency of exciting signals according to the change of the output signal frequency of a the transducer.
2. Description of the Related Art
The conventional ultrasonic transducer while being applied to the distance measurement usually adopts the elements as follows: (1) a micro controller: for generating a frequency of the exciting signal equivalent to the output signal frequency of said transducer; (2) a transformer: for ascending the voltage of the clock signal for the transducer; (3) a transducer: for emitting and receiving an ultrasonic signal; (4) an amplifier: for amplifying the small signal received by said transducer. The signal frequency generated by the conventional micro controller is fixed and independent from the variation of the elements or temperature. Such an application relies on an accurate transducer with high manufacturing cost and disadvantage to the product price.
Hence, it is imperative how to come out an apparatus for auto calibration for a transducer and the method therefore, by the approach so as the micro controller can be dynamically calibrating the frequency of the exciting signal according to the output signal variation of the transducer, and the best transmitting effect can be achieved without being suffered from the variation of external environment such as the temperature, humidity change.